Manufacture of molten metals.



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Y .L TENTED Ami. T1"` 19os..\ A H. THWAITE a W. DBPRES v MANUFACTURE op MOLTEN METALS.

ffmz'z APPLICATION FILED AUG. 9,

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To nl! whom it 'may concern:

Be 1t known that we, BENJAMIN How-'ARTE THwarrE, civil engineer, of 29 Great George street, lVestminster, London, England, and Voir DEFRrEs, mechanical engineer, of 147 Houndsditch, London, England, have invented a certain new and useful Improvement in the Manufacture of Molten Metals, of which the following is a full, clear, and exact descri tion, and for which we have applied for etters Patent in Great Britain, Xo. 28,573, dated December 14, 1906.

The 'purpose of this invention is to obtain a more. complete control over the composition of certain molten metals, such for example as steel, in the preparation of which large quantities of air or gas ma be forced der pressure through the mo ten metal,

"and to shorten the process of manufacture VIAivhlch has been necessary hitherto for obitaining and ref'ming a homogeneous product.

ltonsists substantially in a process of and 1n airs for using the blast to determine in the mo teiimetal a systematic circulation during the continuance of which ap ropriate special treatmenttxmay be applic( y at a deiinitc point or\dfimte points in the vessel containing the` metal, past which point or points fresh )ortins of the metal are continually broug t.

The characteristic feature of the present invention is the employment of pneumatic means with mechanical structure to reduce a continuous circulation of metal oth to and from the surface .and in and out of separate chambers, which chambers are wholly within the space occupied by the metal and wholly below its surface. In this manner we obtain a more rapid and complete mixture of the substances out of which the metal is manufactured, and the special treatment, if any, is applied directly to a much larger p roportion o the metallic mass than 1n existing processes, so that a homogeneous product of desired com )osition is obtained more quickly and with greater certainty than is .usually practicable.

A construction and operation embodying this process would be as follows, the description referring to 'the accompanyingr drawings in which Figure 1 is a sectional elevation of an in1- proved apparatus constructed in accordance wit-h the invention, on line 1-1 of Fig. 2. Fig. 2 is a similar view on line 2-2 of Fig. 1. Fig. 3 is a cross section of the hollow trun- THWAITE *XXD WOLF DEFRIES, OF LONDON,

Specification of Letters Patent. Application filed August 9, 1907. Serial No. 387:776.

NITED srnrns PATENT orFrcE.

GLAND.

Patented Aug. 11, 1908.

nion on line 3 3 of Fig. 2. Figs. 4 to 7, are views in sectional elevation but on a smaller scale of modified shapes of the apparatus illustrated in Fig. 1.

AThe metallic mass intended is run into a vessel for treatment A composed, F ig. 1, of two vertical tubular limbs a, b communicating with each other through a continuous passage c in the lower part of the vessel and raving an air s )ace (l closed at to i and bottom between the inner faces of the vertical limbs a, b, 'extending from the top of ,the level of communication to the underside of the` 4upper level above which the tubes coalesce to form a common chamber e. The external part of this vessel is made preferably in three or more portions united by lange rings A1 the upper and lower portions being preferably split verticall as at flange joint A2 for convenience of ining. The upper part e is contracted into a throat e2 some Bessemer converter. i

The vessel A is lined with suitable refraca height as to overflow the top of the tubular limbs a, b, into the chamber e forming the upper part of the vessel which connects the tubular limbs, so as to provide a continuous volume of liquid metal above which the slag floats. At' a suitable point in the lower part of the vessel, twyers f are arranged through which ai r delive red under pressure by pipes k, c can be forced up one of the two vert-ical limbs. pressure of air in our apparatus the introduction of sucli air determines a vigorous cir- ,vessel is tilted andthe culation of the molten metal, which flows up one limb a of the vessel and down the other limb b. One or more supplementary twyers f1, to which air is led through a branch pipe,"

k2, may be arranged in the upperpart of the vessel to assist the downwar( flow through the limb b. if the metal in its downward circulation carries with it the slag or some proportion of it, that proportion will inthis way be mixed more intimately with the mass of the metal than if it lay merely on the sur, face and it will jinally settle out when the circulation is consequently finished.

The shape of the vessel isnot limited to the precise form above described; we mayfor instance, bend one limb roundcn itself and arrange it so as to reenter at a point below the free surface, the blast what of the form of that of an ordinary tory material B.A The metal is filled to such By employing a suitable being introduced so i f at or about the base of the shortierllimb as yinclose the blast open at bottom, at or about the base ofi y air supply'by means of ilexible metallic tubes shown in F ig. 4. Alternatively we may divide the vessel, which in such c:1se`niigl1tbe, for exam ile, egg-shaped, by a vertical diaphragm 1 of suitaihe relractory inaterial right across the vessel, and open or furnished with passages at bottom, and stoppingshort of or perforated at the top. so as to permit the vigorous circulation of the metal when a blast is sent up one of the two cha mben, into which the vessel" is divided: such arrangement is shown in Fig. Alternatively we may as shown in F ig. 6 make the diaphragm last mentioned of an annular form, such as a hollow cylinder or cone di, wholly or partly which we letin the twer blast vertically upwards. A contraction may if desired be formed opposite t-he twyers f or at other suitable peint. or points by forming an erilargement or enlargements on the cone or its lining, or some portion of lining in the neighborhood of the twyer may be shaped so as to as it leaves the twyermouth and act as a circulating ejector.

lVhen it is desired to apply this system to an existing converter otherwise than b v the means hereinbetore described, an external vertical tube b lined with refractory material may be connected, see Fig. 7, to the con` vertel' at two points at di'erent levels below the surface of the liquid, at the lower of which a twycrf1 is provided delivering a horizontal blast to force metal over the ordinary twyer or tnyers f delivering a vertical blast from the center of the bottom of the vessel, and so connecting the metal in the vessel A and the external tube l by a. continuous circulation. The essential part of the arrangements, whether in respect of the shape of the apparatus or the nature and direction of the blast is in fact that it should be such that a definite circulation through the length of a continuous passage in the lower part. of the vessel should be established in the molten liquid so as to conyey the metal continuously to and from its surface in the manner common to each of the examples which we have given'.

In order to utilize the products of this process for assisting to maintain the temperature of the charge, when they are combustible and would ordinarily be consumed outside the vessel, a branch may be taken ofi the furnis led with suitable valves or otherwise, and air may be led through it and delivered above the surface of the metal, so as to burn within the vessel anyearbon monoxid, orother combustible gas that may be given off.

The air supply may be provided in the usual manner; but when the duration of the blowing process and the number of veels are not sufliciently large to keep the blowing constant during the day, the air may be the metal to maintain it fluid, or if for lother reason it may be desirable, the reducing livel-ing under relatively high pressure into -usual contrivanee for t-he purpose of pouring.

The girdle z is clamped between cheek plates y11 which are bolted to collarslz: keyed on the axle g. In the form -first above described, see Figs. 1 and 2 the trunnions may afford a continuous axis, passing between the two vertical limbs (L b, and it may be hollowed in part as at g and provided with suitable ports g2 toserve for the introduction of air through the pipe Fig. 3, upon the vessel being rotated through a given angle from the horizontal in the usual way. The vessel is shown journaledat l on pedestals nt and its axle g is itted with\a worm wheel or segment n which may be rotated by means o`\a worm in the well known manner. i

Apart from the uses hereinbefore described, the following will illustrate the`\\uses which may be made of the systematic circulation of the metal past a given point or given points. It it be desired to introduce purifying or alloying substances they may be introduced on to the surface of the molten metal in the usual way or through a separate aperture in the upper partof the vessel, or they may be introduced by itself. If it be desired to reduce the metal, a reducing gas may be introduced instead of or in succession to the blast, either through the same or alternative twyers of whici the pneumatic operation is similar to that of the air twyeis. If it is not convenient to intro` duce such reducing gases under substantial pressure, they may be applied iimnediatelv obvious means with the blast after the air blast has been shut oft' and before the circulation of the metal has stopped. If there is not sufficient heat within the mass of any gas may consist of or be accompanied by carbon or other suitable compounds of which the heat of combustion may com )ensate sufficiently forthe heat lost in the ret uction. If it be desired that the metal should have an increased proportion of carbon or any element which would be separated from a. gas or vapor under the conditions in question, a suitable gas or vapor may be introduced in a suitable manner.

For the convenience of foundry use, the vessel may be mounted on a wheeled or portable frame` and either connected with the blast by flexible tube or joined up with a highderived from a motor and compressor delpressure air main running rotuid the foundry.

45 tory material and comprising similar este Having tlius described our invention what 7. Foriuse in the manufacture of molten we claim as such and desire to secure b v Let4 metals, a rotatable vessel lined with refrac- 60 ters Patent is tory material and `com )rising ascending and 1. The combination of a vessel adapted to descending limbs, a last pipe delivering centaine charge of molten metal, and res-ans along one of said limbs and a second blast j for -introducing a. blast below the level or' :he pipe delivering along the other of said limbs,

metal to maintain the molten metal in eonsaid blasts serving to circulate the metal con- 65 tinuous circulation to and from the surface. tinuously to and from the surface and both said vessel having its interior fashioned vfriili being arranged toenter the vessel below the a. continuous passage having separate ways surface of the molten metal.

for t-lie respective movements of the molten S. For use in the manufacture of molten I mass. metals, a vessel lined with refractory mate- 70 2. The combination with a vessel adapted rial and composed of two similar vertical tui to contain a charge of molten metal, saisi vesbular limbs said limbs communicating with A sel having a continuous passage with sepaeach other through a continuous passage in g rate ways for the respective movements of the lower part of the vessel, a blast pi )e in- 'the molten met-al, and means for introducing trodiiced into the lower part of one oi said 75 fii'st and second blasts into the separate vrsys limbs, said blast intended to circulate said of the vessel, said blasts respectively acting molten metal continuously to and from the in the upward and downward directions so surface of the metal, and said vessel being 'as to cause the metal to circulate detistely mounted on bearings whereby it may be tiltand continuously to and from the surface. ed in the manner of'a Bessemer converter. 80

3. The combination with a vessel aiispied 9. For use in t-he manufacture of molten to contain a molten met-al` said vessel having metals, a vessel lined with refractory matealiiiib for ascending metal and asecond limb rial and composed of two vertical tubular `for descending metal, and means disposed limbs, said limbs coliiiiiunicatiiig with each below the suiface of the molten metal; for other through a continuous passage in the 85 causing the systematic and continuous cireulower part of the vessel, a blast pipe introlation of the metal up and down the respecduced into the lower part of one of said limbs,

tive limbs to and from the surface of the a second blast pipe introduced through the molten metal. vessel and acting in direction opposite to the 4. The combination with a vessel ads;- .cd first, said blasts intended to circulate sa-id 90 to contain molten metal, said vessel listing molten metal continuously to and from the alimb for ascending metal and aseconci limb surface of the metal, and said vessel being 3:3 for descending metal, said limbs ceniieeiiiig mounted on bearings whereby it may be tiltto form a continuous passage, twvers for ined in the manner of a Bessemer converter. troducing a blast into cach of said pssssges 10. For use in the manufacture of molten 95 below the surface of the metal, and in oppometals, a vessel lined with refractory matesite directions, one of said blasts causing the rial and composed of two similar vertical tumetal to flow up and the other down the rebular limbs, said limbs communicating with spective limbs to and from the surface of the each other through a continuous passa-ge in i molten metal. the lower part of the vessel, a blast pipe in- 100 Y 5. F or use in the manufacture of renten trodiiced into the lower part of onel of said metals, a rotatable vessel lined with re sclimbs, said blast intended to circulate said ndmolten metal continuously to and from the ing and descending limbs, said vessel surface of the metal, said vessel being made ,i a blast pipe introduced at the base of o in a number of portions united by flange 105 i said limbs for the purpose of circulating the rings and having an upper part contracted metal continuously to and from the sur" te. iiito a throat, an axle on which said vessel is tLvYgFor use in the manufacture of ril n mounted and operating means whereby said metals, a rotatable vessel lined with rer-:ses vessel may be partly rotated.

tory material and comprising ascendiig snd In witness whereof we have hereunto set 110 4descending limbs, a blast pipe delivering our hands in presence of twe witnesses. along one of said limbs and a second irisst. BENJAMIN HOWARTII THWAITE.

pipe delivering along the other of said ii ibs WOLF DEFRIES.

in a direction op )osite to the first, said bis-sts lVitnesses: servingtgcircuiate the metal continuously GE-o. J. B. FR..\NKLIN,

to and fromthe surface.- T. J. OSMAN. 

